1. Field
This application relates to toners for developing electrostatic images and production methods thereof.
2. Description of Related Art
Methods of visualizing image information via electrostatic images such as electrophotographic methods are currently used in various fields. In the electrophotographic methods, after uniformly charging a photoreceptor surface, electrostatic images are formed on the photoreceptor surface, and an electrostatic image is developed by a developer including a toner and is visualized as a toner image. This toner image is transferred and fused to a recording medium to form an image. The developer may be a two-component developer including a toner and a carrier, or a one-component developer consisting of a magnetic toner or a non-magnetic toner alone.
A toner may be prepared by a kneading and grinding method wherein a thermoplastic resin is melt-kneaded together with colorants such as a pigment, a charge control agent, and a release agent such as a wax, and is pulverized and sieved after being cooled. In the kneading and grinding method, a shape and a surface structure of a toner are irregular, and reliability deterioration such as image quality degradation due to charge deterioration of the developer, toner scattering, and developability deterioration occurs.
A method of producing the toner by an emulsion polymerization aggregation method capable of controlling the toner shape and the toner surface structure has been proposed. In this method, resin particulate dispersion prepared by emulsion polymerization and a colorant particle dispersion in which a colorant is dispersed in the solvent are mixed and an agglomeration product corresponding to a toner particle diameter is formed. The formed agglomeration product is heated to be fused and united, and a toner particle of a desired particle diameter is obtained. According to this method, a small particle diameter of the toner particle is not only facilitated, but also an improved particle size distribution may be obtained.
In a digital full color copy machine, a color image of an original copy is color-separated through blue, green, and red color filters, and then obtained latent images corresponding to the color image of the original copy are developed using yellow, magenta, and cyan developers respectively complementary to the blue, green, and red color separations of the color image of the original copy and a black developer. A colorant in each color developer may have an influence on image quality (particularly, a color tone and transparency) or color reproducibility.